The use of a hand operated pointing device for use with a computer and its display has become almost universal. One form of the various types of pointing devices is the optical pointing device. In one form of an optical pointing device, a light source within an optical pointing device illuminates a navigation surface, such as a finger or a desktop, that is external to the pointing device. Light is reflected off the navigation surface and onto an image sensor within the optical pointing device for detection as relative movement information as the pointing device is moved relative to the navigation surface. This information is used to direct a corresponding movement of a screen pointer.
Conventional imaging surfaces, such as fingertips, desktops, mouse pads, etc. typically have some noise associated with them due to dirt, surface irregularities, etc. that can interfere with generating accurate movement information. While a pointing device can control the light source and the sensor package, the quality and type of navigation surface is typically chosen by the user of the pointing device. Despite many approaches to compensating for varying types of navigation surfaces (e.g., highly reflective, highly absorbing, dirty, etc.), the quality of the navigation surface still affects performance of the optical pointing devices.
Conventional pointing devices are often too large for smaller applications, such as personal digital assistants, mobile phones, handheld computers, portable audio players, etc. In some instances, a conventional pointing device is poorly adapted to execute new functions of evolving electronic devices, as well to accommodate the widely varying shapes and configurations of these new class of electronic devices.
Accordingly, manufacturers and designers of electronic devices still face challenges in reducing the size of pointing devices while enhancing the accuracy, adaptability, and effectiveness of those pointing devices.